# Stats hooks

## StatsFactory

### StatsFactory.hooks.extract

A HookMap, called when generating the specified stats item.

- **Type:** `HookMap<SyncBailHook<[Object, any, StatsFactoryContext], undefined>>`
- **Arguments:**
  - `Object`: result stats item object which properties should be added.
  - `Class`: the original data of the stats item
  - `StatsFactoryContext`: generating context

```ts
type StatsFactoryContext = {
  type: string;
  makePathsRelative?: ((arg0: string) => string) | undefined;
  compilation?: Compilation | undefined;
  cachedGetErrors?: ((arg0: Compilation) => JsStatsError[]) | undefined;
  cachedGetWarnings?: ((arg0: Compilation) => JsStatsWarning[]) | undefined;
};
```

For the following example, the `customProperty` attribute is added in the finally generated `stats.compilation` through `MyPlugin`:

```js
compilation.hooks.statsFactory.tap('MyPlugin', (statsFactory, options) => {
  statsFactory.hooks.extract
    .for('compilation')
    .tap('MyPlugin', (object, compilation) => {
      object.customProperty = MyPlugin.getCustomValue(compilation);
    });
});
```

### StatsFactory.hooks.result

A HookMap, called after generating the specified stats item.

- **Type:** `HookMap<SyncWaterfallHook<[any[], StatsFactoryContext], undefined>>`
- **Arguments:**
  - `any[]`: generated stats item result
  - `StatsFactoryContext`: generating context

## StatsPrinter

### StatsPrinter.hooks.print

A HookMap, called

为一个 HookMap, called when generating the printed string of the specified stats item.

- **Type:** `HookMap<SyncBailHook<[{}, StatsPrinterContext], string>>`
- **Arguments:**
  - `Object`: stats item object
  - `StatsPrinterContext`: printing context

```ts
type StatsPrinterContext = {
  type?: string;
  compilation?: StatsCompilation;
  chunkGroup?: StatsChunkGroup;
  asset?: StatsAsset;
  module?: StatsModule;
  chunk?: StatsChunk;
  moduleReason?: StatsModuleReason;
  bold?: (str: string) => string;
  yellow?: (str: string) => string;
  red?: (str: string) => string;
  green?: (str: string) => string;
  magenta?: (str: string) => string;
  cyan?: (str: string) => string;
  formatFilename?: (file: string, oversize?: boolean) => string;
  formatModuleId?: (id: string) => string;
  formatChunkId?:
    | ((id: string, direction?: 'parent' | 'child' | 'sibling') => string)
    | undefined;
  formatSize?: (size: number) => string;
  formatDateTime?: (dateTime: number) => string;
  formatFlag?: (flag: string) => string;
  formatTime?: (time: number, boldQuantity?: boolean) => string;
  chunkGroupKind?: string;
};
```

### StatsPrinter.hooks.result

A HookMap, called after generating the printed string of the specified stats item.

- **Type:** `HookMap<SyncBailHook<[{}, StatsPrinterContext], string>>`
- **Arguments:**
  - `String`: printed string of the stats item
  - `StatsPrinterContext`: printing context
